Virtual Bench Oscilloscope gives different signal amplitudes for different vertical scales

[ChauH.]

Hi everybody,

I am new to the virtual bench so please correct me if I am wrong. I am having an issue with measuring signal amplitude using the virtual bench oscilloscope. The oscilloscope gives me different signal amplitude values for the same signal whenever I change the vertical sensitivity (i.e. 10mV / div, 20mV / div, etc.) For example, it gives me 2V p-p if I set the vertical scale to be 10 mV / div but 3V p-p if I change the vertical scale to be 20 mV / div. Could any of you help me with this issue? Thank you a lot for your help.

Ch.

[crossrulz]

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ChauH. wrote: For example, it gives me 2V p-p if I set the vertical scale to be 10 mV / div but 3V p-p if I change the vertical scale to be 20 mV / div. Could any of you help me with this issue? Thank you a lot for your help.

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That sounds like your signal is clipping.  Let's do the math.  At 2Vp-p/10mV/div = 200div.  That sounds way too many.  Are you sure you are not on the 100mV and 200mV scales?  Still, your scales are too small for your signal.

[ChauH.]

Thank you for your reply.

I don't think my signal is clipping though because I did not see any clipped part on the oscilloscope. And I am sorry for not making it clear. The numbers I provided are just the example, not the real data. But that's what happened. For a given signal, no matter how small the signal is, the voltage from the oscilloscope is always lower for a lower vertical scale.

I appreciate if you can help me with this issue. I am stuck on my project now.

Thank you a lot.

Ch.

[crossrulz]

Perhaps you should give an actual example that you are seeing for real.  I would expect a little difference just due to how large a step a bit is at the larger scale versus a lower scale (ie you have less resolution at the higher scale therefore the measurement is not as accurate and likely measures higher).

[JoeFriedchicken]

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ChauH. wrote:

I don't think my signal is clipping though because I did not see any clipped part on the oscilloscope. And I am sorry for not making it clear. The numbers I provided are just the example, not the real data. But that's what happened.

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Would you add some screenshots from the application when this happens? I'd like to look at the real data and not a hypothetical 😉